1. Field of the Technology
This invention relates to ramps for loading and unloading from a first level to a second level and to ramps serviceable as temporary bridges. More specifically, the invention relates to a foldable ramp with successively nesting ramp sections hinged together end-to-end in moving between a compact mobile package and an open operational runway.
2. Prior Art
Loading wheeled vehicles, such as motorcycles, small utility vehicles, and lawnmowers, onto larger vehicles, such as pickups or flatbed trucks have been difficult for some time. Ramps for such loading and unloading of vehicles have been proposed but remain inadequate, typically being inconveniently large and heavy or not conveniently storable away from the truck. Perhaps because of the weight and large folded size, ramps have often been integrated into the vehicle, such as a substitute for or integrated with a truck tailgate.
Various types of foldable ramps have been disclosed. It is common for sections to be hinged end to end, such as with ramps with two longitudinal sections connected by a transverse hinge folded in face-to-face opposition, as in U.S. Pat. No. 6,009,587 by Beeman and U.S. Pat. No. 4,761,847 by Savage et al. or such as in ramps with more than two sections that fold together in a “Z” or accordion arrangement, such as in U.S. Pat. No. 5,062,174 by DaSalvo and U.S. Pat. No. 4,944,546 by Keller. These ramps are serviceable but remain unduly large and inconvenient to transport. With the accordion style folding, the ramp load capacity is also necessarily limited by whatever mechanism is employed to keep the upward oriented hinge joint from opening under load. A lightweight portable and compact ramp remains an unresolved requirement.